Explorer heater problem

[Mechanickid]

I have lost the heat in my 91 explorer. What could this be due to? I put it on heat and mellow not cold nor hot air comes from my vents. just air.

 

[engdept]

is the truck warming up to the proper temp? If it isn't, your problem is the t-stat is sticking open.

 

[Ranger44]

T-stat....Heater core....

 

[AllanD]

Actually a non functioning blend door actuator is just as likely.

AD

 

[Mechanickid]

I do believe its the blend door. It just stays cold when I switch to heat and I put a new thermostat in it when I bought the truck. The heater core is not leaking and I don't think its clogged.